In Space Empires 5, not only can you modify weapons, you can invent and create new weapons systems, power sources, etc. by tinkering with the game's weapons list tables.
For those not familiar with the Space Empire series it is a cross between SFB and F&E in that one attempts to explore space, secure and exploit resources, establish colonies and wage war, either to secure borders or to annex planets and star systems.
Ships are designed like SSD boxes, in a UI format. As with SFB, spce inside whatever hull you use is ata premium, so some systems have to be deleted to add in something else. As with SFB and SFC, the internals cost revenue points, which your colonies generate.
Ships have a BPV value, according to your design, and this costs you when churn one out of a shipyard.
The ship's sublight movement cost is according to hull size, as in SFB and SFC, though the number of Ion Plasma Drive boxes wedged into a hull determines the ship's speed, unlike SFB and SFC, where the amount of mass reducing subspace field produced Warp boxes remaining on a ship, determine the speed.... in SFB and SFC speed 30 = lightspeed = 300,000,000 Kliometres per second.
Travel between star systems is by warp jump gates and interplanetary travel is by Ion plasma drive.
Basically Space Empires 5 is heavily influenced by SFB and F&E and draw heavily from it in inspiration.
There are fighters.
If SFC 2 was crossed with Space Empires 5, I think we'd end up with what folks would like SFC 4 should be like. The campaign and colonising aspect, along with the logistics, designing various vessels, fighters, stations and shipyards in game, would be great.
The battles are more on the lines of Home World crossed with SFC 2.
All ship and weapons models are .X file types.
My son, Robert, has been gradually adding in SFB style weaponry, plus a few of his own ideas.
He's also created a few new power sources, such as a very low power radioisotope generator and a fission reactor, for a lower tech level development.
The stock weapons list covers more than SFC (and has many SFB Omega Quadrant race weapons in) with Phaser and Disrupter Outputs rated from 1 to 5. The same goes for Particle Beam Cannons, Photons and a whole bags of Sci-Fi weapons.
Perhaps a close examination of how Space Empires 5 does its weapons so that players can create their own boxes for use in ship design would be the way to go.