One of my client has a .de domain. I have VPS from Linode and I am pretty happy with them. Domain is registered with godaddy. DE domains Name servers have some restrictions. I first try to move name server to Linode. I set TTL values accordingly but couldn't succeed with Linode. Then try to configure name server of godaddy with adding A and CNAME record to point my Linode VPS with no success. Now I have one option I look forward good VPS or shared hosting that have a name server works with de domains. I found a shared hosting but they dont have php-curl installed. If you ever hosted a de domain please share your experience.
If you purchased the .DE domain from GoDaddy, you should be able to use their nameservers. I believe the restrictions you speak of are for actually registering the domains, not where the nameservers are located. What issues were you encountering with GoDaddy? Was it throwing an error when you tried to add the records? If so, you should probably speak to their support.