Whenever I advise companies or foreign domainers concerning domain management issues, I recommend registrars which are able to secure multi-TLD offer in 'one stop shop' - it really makes things easier, the more when you have more than few hundreds domains.
Personally, I have 1500+ of .PL with
http://EuroDNS.com and I am sattisfied.
When you sell your domain services to corporates, like I do besides being a domainer, there is no other reasonable choice than companies like EuroDNS which gives all worldwide TLDs.