I found two broken toaster until now, remembering that Fallout New Vegas has crazy joke about those I was avoiding to sell them but now I can't find those items on my PC's inventories.

I'm very sure I never sold them (and already went to all the stores to look for them), but nothing... My question is "the toaster appear as all the other items or I just got screwed?

Sorry for the -very- late reply, I'm quite new to the forums, so I noticed your topic just now.
There are only 4 toasters in the entire game, so if you lost yours you cannot find replacements.
They are not very useful, anyway: near the end of the game, if you have the "toaster repair" ability, you can gain some items... but by that point, you should have plenty of better equipment, anyway! So don't worry, you have missed almost nothing!