Hi Martin,
I know you love multimeters that do logging. For many of your viewers, they may not be able to afford a Fluke 289, Agilent U1272A, or the beloved Metrix MTX3282 so here is a potential low cost one?
Make sure to read through the comment/review section as others have documented the limitations (RS232) and workarounds. For $30, it wil obviously have limitations and trade offs, but it could be enough for casual users?
http://www.amazon.com/TekPower-TP4000ZC-RS232-Interaced-Ranging-Multimeter/dp/B000OPDFLMI noticed a few people who bought them did it for solar power stuff as well.
Anyway, something to think about for a future video blog.