I do recommend looking up the thread on the PEG since I think it would provide you with many ideas and the arguments about why some of them are bad ideas. Your statement that one can't use temp-tables in .cls files is not correct, though perhaps you meant that you couldn't make it a shared temp-table.
The core principle here is that a class is supposed to encapsulate its implementation so that, from the outside, one can't tell whether it is using a temp-table, database table, work-table, linked list, bunch of variables or whatever. Put all the logic of manipulating the temp-table inside the class and expose methods which relate to behavior, not implementation.