IMHO, disabling URL opens is an excuse. There's no good reason to do it.
In fact, if there's another way to open URLs (cURL) then what's the difference?
Anyway, to your problem....
Your bad_url and good_url will work find. They are just browser redirects.
Use of FMBadHandler (make sure you have v1.12) should be OK too, as it uses "fsockopen" to open the return link (unless they've disabled that too ).
The problem you may have is with templates. But, only if you're using $TEMPLATEURL instead of $TEMPLATEDIR.
If you are using $TEMPLATEURL, we would need to change the mechanism for opening URLs.
We probably won't implement cURL because not every server has it.
But, if fsockopen works, then we can switch all the code to use that mechanism.
Of course, we can't do that in a hurry. So, you can either use static templates with $TEMPLATEDIR or switch to a more flexible hosting company.