I was looking at prices for dumb cordless dual line handsets. For something dumber than the simplest Bluetooth GSM handset you still pay at least $200US.
Is there some sort of dual line SIP or other appliance for sending my dual land line to my N900 off the shelf or would it require building a small Asterisk device?
I would like to eliminate all but two emergency wired handsets for the land line in my home/office since a cordless is just extra clutter.

Sounds like you would need a DECT system...

Not sure if there is anything specific for n900 but you could look through here for info http://dect.osmocom.org/trac/dect

However these require a base station to operate... which could be a bloody useful implementation of the Raspberry Pi? This might be worth looking into?

I have Asterisk with Google Voice set up at home as a virtual machine (read no extra hardware required).

Works great. I use PBX in a Flash.

slaapliedje

Interesting... Only shame about the Google part since I distrust all things Google. Would it work with any random SIP?

If you create a asterisk server at home and have a VIOP/landline gateway - Cisco & netgear make them you could do it.

There is a thread on here somewhere, but my search-fu has deserted me at the minute