I have inherited a client project that involves a number of EE installs (6 in all, though some are MSMs themselves, so total number of sites is ~10) which I would like to merge into a single MSM install.
One of these installs is EE1, the rest are various versions of EE2. All use Matrix, Playa and Assets. The EE1 site could be migrated to EE2 though (the DB at least).
I'm trying to work out the best way of migrating the data (as far as I am aware there is no first party tool to import an existing site into an MSM install).
At the moment our approach is an increasing complex custom script that maps data from the columns of the old DB to the (manually created in the case of exp_channel_titles/exp_channel_data) columns in the new db. I'm concerned that this is actually such a complex task that we're going to miss something in the process though.
If you have accomplished this task in the past, how did you go about it? What approach/tools did you use etc.