I have to agree with KRyan, that it will have to be undefined and left to the GM.
That being said, if we look at some "moveable" extradimensional spaces, we can argue that rope trick may have to be stationary.
If we look at portable hole...
Aura strong conjuration; CL 12th
Slot none; Price 20,000 gp; Weight —
A portable hole is a circle of cloth spun from the webs of a phase spider interwoven with strands of ether and beams of starlight, resulting in a portable extradimensional space. When opened fully, a portable hole is 6 feet in diameter, but it can be folded up to be as small as a pocket handkerchief. When spread upon any surface, it causes an extradimensional space 10 feet deep to come into being. This hole can be picked up from inside or out by simply taking hold of the edges of the cloth and folding it up. Either way, the entrance disappears, but anything inside the hole remains, traveling with the item.
The only air in the hole is that which enters when the hole is opened. It contains enough air to supply one Medium creature or two Small creatures for 10 minutes. The cloth does not accumulate weight even if its hole is filled. Each portable hole opens on its own particular nondimensional space. If a bag of holding is placed within a portable hole, a rift to the Astral Plane is torn in that place. Both the bag and the cloth are sucked into the void and forever lost. If a portable hole is placed within a bag of holding, it opens a gate to the Astral Plane. The hole, the bag, and any creatures within a 10-foot radius are drawn there, the portable hole and bag of holding being destroyed in the process.
Requirements Craft Wondrous Item, plane shift; Cost 10,000 gp>
We see that it requires plane shift to create, which is a 5th level spell, opposed to the 2nd level rope trick is.
Also, we can look at Bag of Holding...
BAG OF HOLDING
Aura moderate conjuration; CL 9th
Slot none; Price see below; Weight see below
This appears to be a common cloth sack about 2 feet by 4 feet in size. The bag of holding opens into a nondimensional space: its inside is larger than its outside dimensions. Regardless of what is put into the bag, it weighs a fixed amount. This weight, and the limits in weight and volume of the bag's contents, depend on the bag's type, as shown on the table below.
Bag Bag Weight Contents Limit Contents Volume Limit Market Price
Type I 15 lbs. 250 lbs. 30 cubic ft. 2,500 gp
Type II 25 lbs. 500 lbs. 70 cubic ft. 5,000 gp
Type III 35 lbs. 1,000 lbs. 150 cubic ft. 7,400 gp
Type IV 60 lbs. 1,500 lbs. 250 cubic ft. 10,000 gp
If a bag of holding is overloaded, or if sharp objects pierce it (from inside or outside), the bag immediately ruptures and is ruined, and all contents are lost forever. If a bag of holding is turned inside out, all of its contents spill out, unharmed, but the bag must be put right before it can be used again. If living creatures are placed within the bag, they can survive for up to 10 minutes, after which time they suffocate. Retrieving a specific item from a bag of holding is a move action, unless the bag contains more than an ordinary backpack would hold, in which case retrieving a specific item is a full-round action. Magic items placed inside the bag do not offer any benefit to the character carrying the bag.
If a bag of holding is placed within a portable hole, a rift to the Astral Plane is torn in the space: bag and hole alike are sucked into the void and forever lost. If a portable hole is placed within a bag of holding, it opens a gate to the Astral Plane: the hole, the bag, and any creatures within a 10-foot radius are drawn there, destroying the portable hole and bag of holding in the process.
Requirements Craft Wondrous Item, secret chest; Cost 1,250 gp (type I), 2,500 gp (type II), 3,700 gp (type III), 5,000 gp (type IV)
You see secret chest, which is also a 5th level spell needed to create.
Lastly, there is Handy Haversack...
Aura moderate conjuration; CL 9th
Slot none; Price 2,000 gp; Weight 5 lbs.
A backpack of this sort appears to be well made, well used, and quite ordinary. It is constructed of finely tanned leather, and the straps have brass hardware and buckles. It has two side pouches, each of which appears large enough to hold about a quart of material. In fact, each is like a bag of holding and can actually hold material of as much as 2 cubic feet in volume or 20 pounds in weight. The large central portion of the pack can contain up to 8 cubic feet or 80 pounds of material. Even when so filled, the backpack always weighs only 5 pounds.
While such storage is useful enough, the pack has an even greater power. When the wearer reaches into it for a specific item, that item is always on top. Thus, no digging around and fumbling is ever necessary to find what a haversack contains. Retrieving any specific item from a haversack is a move action, but it does not provoke the attacks of opportunity that retrieving a stored item usually does.
Requirements Craft Wondrous Item, secret chest; Cost 1,000 gp
Also taking a 5th level spell.
You can see all of those are actually much smaller than the space created by rope trick, (8 people of any size) and can be moved around, especially the portable hole, it is very small. Yet they all take much higher level spells than rope trick.
So from that, you could assume rope trick is stationary, but again its all conjecture.