how to combine two lists without join?

[Gaudenz Steinlin <gaudenz@soziologie.ch>]

To integrate discover2 into hw-detect I need to combine to lists into
one without join (which is not available in busybox and not on d-i
images):

MODEL_INFOS=$(discover -t all)
MODULES=$(discover --data-path=linux/module/name all)

MODEL_INFOS and MODULES now contain a list of vendor/model strings and
kernel modules (newline separated). I now want to combine these two
lists to one list with lines of the following form:

module:model_info

How can this be done with only the tools available on d-i images? Eric
Gillespie of Progeny simply keeps repeating that it should be easy and
I'm almost convinced that I might be stupid, but me and pere didn't find
an easy way to achieve this. The only thing I can imaging is writing a
little C program that does this. 

Thanks for your help

Gaudenz