you could try this ugly 'MONSTER', works to 9,999,999,999,999.99 (which is the 15 digits of significance Excel allows.it will go to 999,999,999,999,999.00 as long as your willing to lose the pennies and dimes as you get larger, I am working on a better one)
(Note- My original formula for this uses named arrays and named formulas to shorten the actual formula)
Hope this helps 
EDIT-
RECQUIRES 2007 or higher, this particular version is 1700-1800 characters long, so pre 2007 versions will not accept it (as I said, still working on a better one)
Edit 2 -
Closer to 8000 chars, sorry
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