I use 007Names for domains with the standard French/Spanish/German accented letters like é,ë,ö,õ,ä,í,.etc because they offer the full array of services like Free URL redirect,webmail,etc.
I use Idotz.net for all other types of accented letters because 007Names sometimes has trouble regging them.Idotz and Dotster were the only places I found that allowed registration of the 1-letter domains.