According to https://www.arin.net/resources/request/reassignments.html it's actually mandatory to provide whois tracking for assignments /29 or shorter prefix, and optional for /30 or longer prefix. I can't find any reason they wouldn't be able to provide it if they wanted to.

Edit: definitely possible http://lowendtalk.com/discussion/12406/which-providers-provi...

So you shouldn't call MIPSpace stupid, thanks.