I think bidding on sq/ft is suicide on a resturaunt. (Especially at $5!) It's nothing like an office, or other types of commercial. As the kitchen is filled with equipment, so that blows the whole sqft process as 1 sqft of it could run you $150+! And the dining area could be all high-end or specialized fixtures. Why not just sit down with the plans and plot it out? Bid the dated and spec'ed set! You don't want to make no money, or worse, loose it. If it's a chain, and you get it, you could use the first price as a basis for the second, but walking in blind may be exactly what they want you to do. (If you haven't worked with the general, or client before on this type of work. Be wary, trust no one!) Resturuaunt Franchisers are cut-throat shisters! As long as they know, that you know that, you'll be on more level ground.
Mark Heller "Well - I oughta....." -Jackie Gleason
I have never even looked to see what the $/ft2 came in at, so I can't tell you what I've done them for. But I did happen to have an old print here for a ground up high-end type resturant that I didn't get. I was too high. The GC told me how far off I was, so I know what it was awarded at. Somewhere around $242,000 and the sq. ftage was 8600. So that gives you around $28 per. But what you don't see included in the sq. ftage is the parking lot lighting, the outdoor dining area, the landscape lighting, the sign at the end of the parking lot, etc.
As it's been said, the kitchen is too big a variable. just the percentage of total square footage as being kitchen is a big variable. Then in that exact same sized space, they may want to add a 70 amp booster heater to the dishwasher, or maybe not. The row of heat lamps in one resturant may be 15 appliances in another.
The advice so far is right on, one of our local EC's went in on a 8,000 plus sq and bid a little under $250,000, he only lost 15,000 when it was all over, he was planning on getting in, to get more work, they milked him then found another greene, for the next project.