There are two problems: "senoritas" probably would become obsolete in a few years if the IDN goes into wide use, since the Spanish word, which is a plural, is "señoritas” (it means, more or less, Miss.) There is a case, with iespana.com (which is a representation of iEspaña.com) that has been a big hit, but I am understand a lot of money went into promoting the name.
The other problem is that, for some strange reasoning, some domain owners and developers have avoided the .us extension with Spanish word --unless is a very important keyword, as, let's say, banco, abogado, medico, etc. There are hundreds of very sought-after words ("telenovela," Spanish word for "soap opera" comes to mind) which nobody ever bothered to even register.
Having said that, though, I think senoritas.us probably would be very useful to the owners of the other "big" extensions (.com, .net) or to someone who would develop it into a teen site. A dating site could be another posibility, even though they would almost have to brand it as such.
In conlusion, I think you probably could get between $30 and $60 for it. If you develop it, depending on the direction you give to it, mid to high $xxx; maybe even low $xxxx.
Good luck with it.