Pete -
Recommend not going with a wooden structure... if you are going to weld in it; then the insurance will be crazy expensive.
I recently put up a new 24 x 22 foot garage / shop and used a metal building kit (vendor customizes the kit to meet your needs and put it up on ebay with a buy it now option). It was far less expensive that a wood structure quoted by any of the local companies and it was crazy simple to put up on a simple slab. Big benefit is that it is essentially impossible to set on fire...
I will PM you the vendor specifics when I get back to house tonight. I also have a ton of build pix of it going up if you (or others) want a copy.
/K