You might find it helpfull to take a look at the "archetypal" example force lists created by Demian. I'm sure he can be persuaded to provide you with a link (or give me permission to publish the links to PDFs at my home page). There is a list for Star Marines and Space Thugs. The latter is build to handle Orkish style forces, while the inspiration for the first should be obvious from the name.

I would make them TL3 but mostly limit their weapon frame options to TL2 compatible stuff as their standard weapons aren't very effective.

In tournaments, I believe that's a no. Otherwise, there is no such limitation. A TL2 force might have a hard time taking on a TL3 force tho, but that's as it should be.

Hey Wes,

Glad to hear from a 15mm sci-fi afficianado!  I personally think that 15mm affords the best compromise between paintability and playability, but the market is so dominated by 28mm games that Defiance made it the "default", though we made sure that conversion to 15mm was both easy and allowed for a bit more of a realistic figure to ground scale.

As for your army conversion ideas, as tnjrp suggests, I would make Orks (as they are described in the 40K gameworld) tech level 3.  This is because, despite a low-tech look, they still have alot of unique and powerful weapons and effects, as well as powerful body armor.  It is a bit tough with techno-fantasy armies, however, since they often have basic weapons that seem worse than an early 20th century bolt-action rifle.  This is one reason for the "techno-fantasy genre" rules in the rulebook; to try and better capture the "WWI tactics in a high-tech universe" feel.

For some ideas, here's a link to some generic lists that can be found on the official Defiance web page: 

http://mj12games.com/defiance/armydemos.pdf

I would be greatly interested in links to the manufacturers you mentioned, NoelVH. I've looked at but never bought 15mm vehicles you might be interested in:

http://www.dldproductions.com/

http://www.oldcrowmodels.co.uk/

Demian sez Tech3 for Orks, and I'd say the same (not only for the obvious reason but also...) Warhammer 40K tends to have weak basic weapons, somewhat effective special weapons, and massively powerful heavy weapons, as well as grossly powerful hand-to-hand attacks and, back in the days of 40K when grenades killed people, several of those were pretty devastating too. You'll probably find that the "massive blast that hurts everything and works on everyone" weapons are VERY pricey in Defiance; hence, Tech 3.

I have 2 tanks and 1 VTOL from FroceXXI. I was going to place a another order with him but the owner went on deployment with the US army I think.
But for somr of the conversion armies I am looking into WWI tanks. With some light conversions to them I feel they will look cool.

Wes