Catalyst + crossdev howto or alternatives?

[szatox]

Long story short, I want to setup some tool that will let me periodically build gentoo for foreign (and severely underpowered) architectures.
I already have crossdev toolchain.

I looked into Catalyst docs, but it makes impression as if it wanted to run the foreign toolchain under qemu-user rather than using cross-toolchain. If this is really the case, builds would be unacceptably slow. https://wiki.gentoo.org/wiki/Catalyst

Meanwhile, it seems there were some changes to the way emerge uses various *ROOT variables, so my old way of cross-merging things manually may not work anymore either (and at this point I'm not sure if it's now broken or I'm deviating from my old procedure)

The problem at hand should have been solved a long long time ago in a sensible way. Does anyone here know a solution I could reuse? Any howtos/guides?

[zen_desu]

Long story short, I want to setup some tool that will let me periodically build gentoo for foreign (and severely underpowered) architectures.
I already have crossdev toolchain.

I looked into Catalyst docs, but it makes impression as if it wanted to run the foreign toolchain under qemu-user rather than using cross-toolchain. If this is really the case, builds would be unacceptably slow. https://wiki.gentoo.org/wiki/Catalyst

Meanwhile, it seems there were some changes to the way emerge uses various *ROOT variables, so my old way of cross-merging things manually may not work anymore either (and at this point I'm not sure if it's now broken or I'm deviating from my old procedure)

The problem at hand should have been solved a long long time ago in a sensible way. Does anyone here know a solution I could reuse? Any howtos/guides?

Here be dragons: https://github.com/desultory/genTree

I made this a while back and it kinda sorta does what you described (i was having a hard time with catalyst and wanted to be able to run the builds as a plain user). I've kinda stopped working on it but have used it to make crossdev binpkgs and images.
It's not made for crossdev but has support for making and using crossdev chains within this system

You can also just use crossdev yourself, and treat the /usr/toolchain root as the fs root (with some adjustments).

Keep in mind that sometimes qemu-user is the only real way to build certain packages, not everything plays nice with crossdev.

[szatox]

I must say your tool looks quite impressive
And it should indeed fit my purpose. Thanks, I'll try it