If one desires (virtually all) same sex Tilapia (which could be an advantage for a small micro pond where no breeding was desired) you may be able to get them from a nearby aquaculture-for-food fish farm (there is one within esy driving distance of me where this is an option).
"Live like you'll die tomorrow, but manage your grass like you'll live forever." -S. M. Stirling
Rstringer, I have a seller on ebay that has been fantastic to deal with, I've bought many batches of Blues and raised to intermediates and sold them to folks near me. If you want the source, PM me as I'm not going to take sales away from people that buy space here. These are all 1/2-3/4" fish and to my knowledge, that's not a target for sales here.
It wasn't entirely a guess. For rough estimates of fish lengths, I often use my hand which gives me a ball park length really quick. My first impression at first seeing the photo was >10" but I knew if I guessed too long ... I might get ribbed a little by the crew. That fish probably weighs between .85 and 1.00 lbs depending on available foods and my impression is that it is on the hefty side. A really great fish.