many choices for honda swaps ill show you a few, and YES you can fit a V6 in a 1995 Civic Dx
your options would be this(but not limited to this, also can be turbo'd)
D16z6 swap, B16a2, B16b, B18b1, B18c1, h22a4, k20a2, and many more
proof of the V6 civics built:
http://www.youtube.com/watch?v=GeXCNhHuahY
if you want to spend alot of money and be unique build a civette (civic with corvette motor)
http://www.youtube.com/watch?v=bfR_Ztug9N0