Alright, ChaoticGraviton, I'll post it.
The long and short of this is I'm asking for an aerospike model more indicative of larger scale proposals.
The aerospike model currently in game is a valid physical concept, but has a complete spike for the exhaust to expand against and pumps above the thrust chamber assembly. However, it has been recognised for some time that this arrangement is impractical. This patent from North American Aviation in 1966 details an "aerodynamic spike nozzle," in which the nozzle surface is truncated and a gas is introduced into the resulting void, resulting in the nozzle acting much like it would had it not been truncated at all. There are several reasons for doing this: A complete spike is much heavier than a shorter spike and gas outlet manifold, it provides less surface to cool for a nozzle concept that has been notorious for causing cooling difficulty, and without the long physical spike the overall length of the engine can be much reduced, allowing for more structurally efficient rockets.
The location of the pumps and other plumbing above the thrust chamber also adds to length that doesn't necessarily need to be there. In attempts to build such an engine, and in numerous design concepts, the machinery of the rocket engine has been located within the portion of nozzle wall that does follow the spike profile before truncation. This can be seen in Rocketdyne's "Advanced Cryogenic Rocket Engine Program, Aerospike Nozzle Concept," Volume 1 and Volume 2, where some components of a J-2S engine were modified and repackaged within the nozzle. This arrangement was also employed in the XRS-2200 linear aerospike that others have asked for analogs of. Putting the turbomachinery inside of the nozzle allows for shorter piping, a more compact engine, and so it's easier to integrate into a vehicle.
The combination of these two effects is that the model we have in game for an aerospike nozzle is not very representative of what real world, higher performance aerospkes would actually look like. They incorporate none of those length and weight saving measures, and so are long and unweildy to put on rockets. I'd like to see a second type of toroidal aerospike nozzle added to the game, one more inspired by the 1960s Rocketdyne example: a ring where the combustion chamber(s) are located, a shorter nozzle ramp ending in a truncation rather than a point, and the engine's machinery encapsulated within as space is available there. This will provide a novel rocket engine model to play around with - for some truncation points you end up with an assembly wider than it is long - and I know I'd have a lot of fun with it. Thank you for considering!
A small addendum: Since gas generator engines already have a supply of gas to create the "aero" part of the aerospike, I'd expect that those would have similar specific impulse when used with this new nozzle model as the plain spike, but that closed cycle engines would perform slightly worse with this aerospike than with a plain spike. However, this may be outside the scope of a nozzle model addition, and I only include it here for completeness' sake.
OH YEAH WE NEED THIS