I'm not even sure requests are allowed in this forum, but as I can't seem to find anything discouraging it, and this does allow discussion of concepts, I hope this post is OK. (But then that is what moderators are for!)
There are a number of cool ships in the star wars games that haven't been made for X-Wing Alliance yet. Especially the Jedi Knight and Knights of the Old Republic Games. If anyone is stuck for ideas, but interested in making an opt, how about one of the following. If you are interested, add a post saying so and I will add pics and a detailed description.
Jerec's Super Star Destroyer (JK)
Approximately five times as long as a Imperial SD, but 3x as wide, this is a very long ship. Unlike most SD's this ships hull angles upward underneath, rather than downward, so it does not have the diamond shape (rear-view)
The Doomgiver Super Star Destroyer (JK2)
The Doomgiver is more rectangular in shape than other SD's, with the center third of the forward section missing. Underneath the Doomgiver caries a multitude of special landing craft.
Starforge Modified Starship (Knights of the Old Republic 1 & 2)
Similar in design to Star Destroyers, these craft have a more rounded design, with the centre third of the craft (vertically) absent.
Unmodified Starship (Not featured in game)
Similar in design to SD's, these craft have a more rounded design, making them appear somewhat like a cross between an SD and a Rebel Med Transport.
Republic Frigate (Kotor 1)
Small frigate with a cilindrical body and engine pods slanting vertically downwards towards the rear of the ship, and two large weapons on either side of the forward section.
Republic Frigate 2 (Kotor 1 & 2)
Similar to the original, but with a vertical hammer-head added to the forfard section, with two more large weapons above and below.
The Ravager Star Destroyer (Kotor 2)
Similar in design to the Victory Class Star Destroyer, but without the wings, and on a larger scale.
I can't remember what it is called (JK) You know, the one Kyle stowed away on, the fuel ship thingy.
A vaguely oval body with a rectangular structure protruding downwards.
Goto's Yacht (Kotor 2)
An E shaped craft with a tale. The centre protruding section is the bridge, with the tale directly behind.
The Ebon Hawk (Kotor 1 & 2)
Shaped like the YT-2000, without a gap between the leftmost section and the cockpit.
Telos Shuttle (Kotor 2)
Similar to the Lambda class shuttle, but with a more squat body and shorter centre fin.
Republic Assault Shuttle (Kotor 1 & 2)
A C forms the engines and "arms" of the craft, with a centre elevated arm forming the cockpit.
Star Forge Shuttle (Kotor 1)
Similar in design to the Rep Assault Shuttle, it is much smaller with a more square design.
Starforge Fighter (Kotor 1 & 2)
The centre cockpit is similar to that of a tie Advanced, but the wings sweep forward and are horizontal not vertical. Similar to S-Foils, the wings are folded beneath the fighter when not in combat, to minimize size for easy storage.
Republic Fighter (Kotor 1 & 2)
A long, skinny, very flat fighter. Shaped like an A with the upper portion filled. Between the legs of the A are the engines.
Republic Bomber (Kotor 1)
A tall fighter with a narrow body. Two rectangular engine pods are attached to the upper portion of the craft
G-Wing (Kotor 1 & 2)
Shaped a little like a B, the two outer arms extend beyond the crosspiece, and with a smooth curve like in a C, not the bumpy one of a B. The cockpit is locate at the upper, rear corner (*B), facing forwards towards the curve. A heavy weapons pod is on the other side (.B), with the engines mounted on the centre of the crosspiece (-B).
Mandalorian Basalisk (Kotor 2)
Has a similar appearance to the star viper http://www.abstraction.com/derek2/
, but looks basically like a flying brick.