If you are not using the old domains you should be using a 301 permanent redirect not a 302 temporary (The requested resource resides temporarily under a different URI), you're losing link juice using 302's.
One solution is to setup a shared hosting account on hostmonster or another unlimited hosting provider. Have all your old domains use an .htaccess file to do the 301 to the specific path on your new domain.
Or take a look at the redirect hard link option from dnsmadeeasy http://help.dnsmadeeasy.com/record-entry/http-redirection/
Amazons Route 53 is pretty nice as well and very cheap compared to most other DNS management services.
There's also a few suggestions on redirecting DNS to a file on SO https://stackoverflow.com/questions/6507640/using-dns-to-point-a-domain-to-a-specific-page
Nothing fancy though you'll get the same redirect with the .htacess method.