How to Get SIM Card / Use Cell Phones

Some follow-up questions to the thread at Cell phones with PingYing

Which provider offers the best coverage for rural areas at the east coast? Intuitively it would seem that going with the Chungwa-associated provider would be best in this case - is that correct?

Are there are any cell phones that don’t use SIM cards, i.e., they are hardcoded to the owner and thus known to be worthless to anybody who steals them? (That is the big advantage of Japanese cell phones - nobody here worries about their phones lying around in public places.)

I’d like to have a phone that’s slim (length doesn’t matter), has keys (not a touch screen), and is closed by folding one half over the other (not flat like, for example, the iPhone) - are there any phones of that kind available? (Of course, in any case with hanyu pinyin capability for e-mail, as mentioned above.)

What is the lowest-cost no frills plan for phone and plain e-mail? I don’t need any other of the uncountable services some people have with their portable phones.

How can one get a phone plan (and, for that matter, an internet connection at home) without a guarantor? I don’t mind a reasonable “security deposit” if necessary, but i don’t want to bother anybody to have to sign anything on my behalf.

Thanks for any and all hints…