Adding a package manager to a blfs system
 

Is it possible once the system is up and operational to tap into another distributions package manager repo such as dkpg or rpm to install tertiary level of importance software (eg. office production / video views / ide's)

Yes, it is. I would recommend Slackware's package management system, since the lack of automatic dependency resolving will keep you free of the hassle that you are missing packages (and therefore dependency information) for the base system.

I agree with TobiSGD the slackware package system is very good ( in fact I wrote my own based on the same concepts see here:http://www.linuxquestions.org/questi...7/#post4859506 )

I would not recommend dpkg as it does seem to pull in vast amounts of dependencies for even the smallest programs there also seems to be a lot of trouble installing and setting it up on non deban systems, there are a few posts on this forum about it, rpm would probably be simpler but the debian packages are easier to extract and install manually.

You can use the gentoo package manger portags or slackware slackbuild, they give you FREE!!!!