Watch Out for the Limited Digit Bug

Reading on the sony ericsson W999i (which looks to be a powerful 2.4" display HSDPA capable Walkman slider) over at Mobile Magazine reminded me that Nokia's model designation and Sony Ericsson's naming scheme are limited.
All the names of recent Sony Ericsson models start with a letter and end with three numbers. Nokia uses four digits for most of its phones and the N moniker plus two numbers for its high-end models.
For Sony Ericsson, what happens when all letters and numbers are used? (A000 to Z999). And what will Nokia do if 0000 and 9999, and N00 to N99 are already taken? Admittedly, this will take a while, but with all those new models coming out every month, it'll arrive sooner than we think.
Unless we see new names from Sony Ericsson and Nokia, we'll probably be seeing the Nokia E61i v3.0 in a few years. Or both companies adding another digit to the scheme (introducing the Nokia 63405!). Let's just hope it doesn't get even more confusing when either becomes a reality.