I would be leery of the cheaper file cabinets IF you will be accessing the contents often or if the drawers will be full (or nearly full).

Do you have an office furniture warehouse near you - one that specializes in used office furniture? You might find some really great deals there. We got a walnut veneer lateral file cabinet for $50 that is just gorgeous, I think was made in the 60's or 70's and it's really sturdy. It also weighed a bleeping ton.

If you found a pair of matching, well built oak file cabinets in your dimensions you could have them painted whatever color you wanted, and it would probably be less than the custom ones (more than the Walmart ones) and still be quite sturdy.

From what I can tell, this isn't your typical walmart & co. cheap file cabinet. It weighs 47 lb which should keep it secure even when full. I did a quick look and it seems it is reviewed favorably (overstock and another online retailer).

I wouldn't go custom -- especially if you are going to paint it. I would probably watch CL though, it seems like there are always a large number of file cabs.

Sounds like an interesting room-- love the multi-purposing!

Here is a link that might be useful: A few reviews here