I can't answer your main question, about the ability to have an account with no hosting plan. Hopefully someone else can!
Just wanted to note that, AFAIK, nothing gets "wasted" when you transfer a domain between registrars.
Let's say you have a domain that expires in July 2013 (for example). If you transfer it to another registrar, yes, that other registrar will make you pay an extra year's worth of registration, BUT, after the transfer goes through, the domain will expire in July 2014. So they do force you to pay it, but then they give you the full credit for it, as well.
This is how it worked for me as recently as... late last year, I think was the last time I did a transfer. I was transferring to Dreamhost, but I don't figure it's much different going the other direction.
Hopefully someone else can answer your other question!