Once the OP clarifies exactly what they want to do we can be mores specific about their options, but I have:
1. Domains registered elsewhere but nameserved and hosted here.
2. Domains registered here but hosted elsewhere.
3. Domains registered and hosted here with subdomains hosted elsewhere.
4. Domains registered and hosted here with subdomains hosted at home.
In many cases, the IP hassle that Scott mentions can be mostly worked around by clever use of NS records or CNAME records.
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