I don't know about your electronics knowledge, but if you have a look at the website of Linear Technology you'll find some interesting information about regulators like the LT 1074, LT 1083 and others.
Maxim is not the only company which manufactures these kind of things, and the LT 10xx types (which are easy to get over here!) give you the possibility to replace the MAX 78x without any problem, even with an increase in power (the LT 1083 e. g. gives you up to 7,5A).
For the replacement of the MAX 788 you can also use the LT 1074; you need two additional resistors with a tolerance of 1% to set the output voltage as the LT 1074 doesn't have a fixed output voltage, but that is easy to do.
Thanks for the info. I never heard of linear technology till now. All this while i've been trying to look for alternatives from motorola and national. from the datasheet it looks easy enough to add the extra components into the existing sproggy. But before i do that i'll have to see whether i can get the LT ics easily here in Malaysia. Else i'll be back to square one