That's it, just DC and AC for $1500. So we can assume 1Vpeak max, DC to 1Hz and 0 - 1fA, with a single channel is good enough for your needs. I think I would save the
$1500 and just get a couple of meters and calculate it.
I will be measuring mostly DC power but AC mains power as well.
I need at least 300V, 1KHz, single channel, 10A etc.
Also, a 4 wire measurement would be ideal to avoid incorrect power measurements due to voltage drop.
I like the Metrahit Energy DMM but is only works in 3 wire config...