I'm looking for a truly minimal usable linux install: the only requirement for the install is that it be able to install a .deb file (that has no dependencies) from the local file-system. (I'm assuming that if I can do that, I can then use that to bootstrap to whatever I actually need).
An ideal distor for my needs would consists of a kernel and an initramfs with nothing but dpks and init. In reality, I expect I will have to settle for something between that and DSL.
Edit: I'm not looking for an installer per se, but rather something that could be booted via an ISO or via PXE. It doesn't even need to leave the system in a re-bootable state.
As Linker3000 pointed out, what I'm looking for may be closer to a embedded distro than anything else.