Let me know if you have anything as a collateral except domain names. I can lend you 1.5 BTC
I would accept TLD's (never got an offer tough)... Not these ones tough, and only IF google analytics is properly installed and i get a full insight + raw server logs + proof of income from that domain...
Taking a domain as collateral is a lot harder than taking a lot of other stuff... It requires the lender to properly estimating how much the domain is worth... This means analyzing everything: the domain itself, the age, the past websites that used this tld, the present site, PR, alexa ratings, income, SE traffic, link partners,...
Next to that, there is a technical aspect: the domain should be moved from the person taking a loan to the account (and name) of the lender... A process that takes a lot longer than just locking a bitcointalk account... An escrow is also possible, but you need an escrow that has enough knowlegde about domain transfers and stuff...
Nevertheless, i think a domain CAN be good collateral, but only quality domain and only for really big loans tough, because it would be to much of a hassle for a .5 loan...
Imagine somebody would offer porn.com [NSFW] as a collateral for a 50BTC loan... You would be a fool not to take it