Greetings all, looks like I've been almost a year away from Maemo Talk

So I'm recently playing around my obsoleted N900 trying to install NITDroid N15, as seen here, but some errors keeps me reflashing the phone and trying again.
The real problem here is, every time I do a reflash from scratch, I have to add extras-devel and extras-testing, wait for it to refresh (~20 minutes, and I can't do anything useful when it's ongoing), install rootsh, wait for another 5 minutes to get out of HAM safely, and proceed with what I want to do. The repeated, long process of installing rootsh is totally pissing me off...
Besides, there might be one day when the Maemo repositories all shut down and HAM becomes unusable. Other non-critical softwares can be installed using dpkg **if root access is present**, but what about rootsh itself? If that really happens, how the hell can I get root access?
So based on the 2 points above, I'd like to know one of these:
1) Is there any way to install rootsh without HAM, or say, without network access? Like I prepare a .deb file and install it somehow?
2) (More serious) Is there any way to enable "sudo gainroot / root" command without HAM, or say, without network access? (I heard R&D mode can do it but not sure about how)

Thanks in advance.