Well, first of all, let's wait (and see) for those applications first. It's bad to "optimize" based on assumptions.

Secondly, the limit is artificial, it's only in the UI. You can add as much swap as you want, using the direct Linux methods (there are other such arbitrary values in the UI, for example screen timeouts which can in practice be set to anything).

Thirdly, swap space is meant to keep the system going in peak situations, it's not like it's something you want permanently going on. If you have an application which needs so much room that more of its virtual memory consists of swap than of RAM then you will have severe performance problems, as well as hitting the flash memory hard (lots of cell wear). If you really need that much swap in a nominal situation then either a) the application must be rewritten to need less memory, or b) if the N800 applications come to need that much memory then the device will have to be equipped with more RAM. Time for the N900, in other words.

So far I would say the 128MB RAM in the N800 is quite sufficient, could even be considered quite large (compared to most PDAs, for example), unlike the 64MB in the 770 which was probably a bit on the small side. If you add 128MB swap then you have a total memory size of 256MB, and having more than half of it as flash isn't particularly useful/efficient anyway, as explained above. In other words, I think the UI limit of 128MB swap is reasonable.