I've attached the code for my payment_dpshosted module. (Edit: attachment may not be working so code is here: http://dev.robbiemackay.com/payment_dpshosted.tar.gz )
I think there is yet another module built by Sunny Side Up (sunnysideup.co.nz) available here:
http://sunny.svnrepository.com/sunny-side-up-general/trac.cgi/browser/dpspxpaypayment
or: http://sunny.svnrepository.com/svn/sunny-side-up-general/dpspxpaypayment/
I'm not sure of the state of that one, or what version of ecommerce it runs with.
We have 3 modules for this and some old code in the SS svn, perhaps we should try to merge all the branches?
I've now finished the project that was using this code, but I could spare a few hours to work on it if needed.
We could set up a shared public svn or git repository for all this code (or ask for access to the SS svn) to start with so that people can at least find it easily.