If you mean make your own bathtub that looks like a bathtub, then no. If you mean frame it in and tile it, it's feasable, but would likely cost more than a regular bathtub, especially after the trial and error that usually goes along with your first tile job, and beyond that, this wouldn't be a regular tile job. Remember it would have to be beyond water-proof, this would be a water HOLDING tile job.
I'm with Matt, don't try it. Around here the stores he's referring to are called ReStore's I believe, they take excess donations from H4H projects and sell it to turn into monetary donations.