The wallet stores transactions, which are complex binary data structures. It's really not feasible to build a wallet by hand. It's programs or nothing.
i may be reading the original poster incorrectly, but it may be that all he wants is something that dumps the internal berkeley db structure of wallet.dat to a flat 'textual' file.
if so, you can just use db_dump: http://doc.gnu-darwin.org/dumpload/utility.html
as an additional backup of a wallet.dat, a textual serialization of the data structure can have some value, albeit a fairly marginal value in most cases. 'text' introduces potential character-encoding issues in theory, but in exchange, you get (1) some hedge against potential data-file incompatibilities in the future, and (2) perhaps, if you're smart and careful, a better opportunity to engage in redundant, fault-tolerant backups compared to treating the whole binary file as opaque.
i agree, overall, it's a relatively minor advantage, but i hope this helps.