A quick question about "mixing armies"

[Bruce Willis]

I play Dark Eldar, and I was browsing through the codex when I noticed the book has some vehicles (as well as a couple units, but my main concern is the vehicles) that aren't available as models. So I was wondering if a regular Eldar Wave Serpent, for example, could be customized and painted to look like a Razorwing Jetfighter (one of the nonexistent Dark Eldar vehicles) and be used AS a Razorwing Jetfighter (they look very alike, and could very well BE the same thing, just decked out with skulls and sharp things). Thanks ahead of time for any info/opinions on this!   

[Rurouni Benshin]

Most people are generally very accommodating and understanding when it comes to substituting other models for one another.  That said, in your case, since the DE haven't an actual model of the vehicle you're using, I don't think you'll have a problem.

[Benjamin]

One note in addition to what Benshin wrote. If you have custom or counts-as models, most tournaments will require that you get the models approved in advance. Tournament organizers use the same logic and judgment in approving models, so again, your choices should be fine.

[Chris]

I think a Vyper might be a better size for the fighter than a Wave Serpent, it would also be cheaper.

[Bruce Willis]

Thanks to everyone for the information!