Was a bit hesitant to chime in since I'm working on a comercial endeavor myself using Glest. A lot of details will come up soon 1st quarter of this coming year (hopefully).
I'm a contract graphic artist as well, and 5-10 dollars is very very low. Even at the low spectrum you're looking at about $250+ or more depending per model (this includes all commercial rights to the model).
That's $500 for your entire project?
Normal Maps, Skin and vertex weights, doubles that to about $500. Although on most contracts I charge $1000 for Normal map models ($800 or less if you'll be contracting me for bulk projects).
Animation doubles and sometimes triples that cost. Animation using a small mo-cap rig makes things significantly cheaper as opposed to key framing (as I've been doing currently since I don't have access to a Mo Cap studio). But I suppose you'd be doing the animations yourself.
Please do not get confused with 3D model depots like TurboSquid or ShareCG. The business model there is completely difference since those models are prices for mass sales (You'll find $50 dollar models because they are sold to over 500+ clients). I've dumped work in those places before and that's typically the rates. Time is the big issue. It can take 2 weeks for a single model, 3 weeks to a month if you want it Normal maped. Hence the cost. By the way I'm being very generous with those prices.
A typical triple A game model runs in the $1000's of dollars hence why most studios will hire in-house to keep costs lower (cheaper to just pay a set wage and lay off an art team then to contract out). A model for a game like Call of Duty: Black Ops I've heard of numbers like $10 to $15,000 (which includes all sub-surface materials, shaders, and any special engine related stuff). That doesn't include Mo-cap data or animation.
But you're not doing something like that I don't think. I'm going to assume you wish to do work on par with the base models in Glest? If so you're looking at about $200 per model (non-normal). In your situation it might be cheaper to either model them yourself or go to a CG depot like TurboSquid, ShareCG, or the old Torque engine repositories. You can buy models ready made in bulk for cheap. They also provide services where they will make 3D models for you cheap if you allow them to be sold through their site.
A good place to look for contract work is CGSociety, Polycount, or Game Artisans. Check their Paid Work and Freelance forums and post your details there. Artists there work mostly in Max or Maya. But Blender exporters are easy to get particularly with the new awesome OBJ exporter tools in any of Autodesks products. FBX format also transfers data very easily between multiple platforms (Mudbox, Maya, Max, ZBrush, and even Blender). So obtaining your models and converting to Blender is easy. Although from a professional standpoint I recomend dumping Blender and using Max 8.
Important things in your post (kind of like you did here):
-Name of your Company
-Brief discription of your project (doesn't have to go into details)
-Terms of your contract; Per model basis, bulk, etc.
-Will you require a sample and will you pay for that sample (can be negotiated).
Here's an example of a post:http://www.polycount.com/forum/showthread.php?t=110011
Look into those to get an idea of prices.
Really happy someone else is also working with the Glest engine. If you have any questions feel free to ask!