Since I'm at it anyway I'll keep going 'till I've got it figured out!
The 1 SS Brigade was indeed raised from Totenkopf Verbande. You are completley right on this Chuck. To be more precise:
8. SS-Totenkopfstandarte
circa 2,600 men
Raised 11/39 Cracow from SSTK Std. 4; became part of SS-Brigade 1 (SS Infantry Regiment 1) under Kommandostab RFSS April 1941; then tranferred to 18th SS Horst Wessel Jan. 1944 as SS-Grenadier Regt. 39. Directly involved in Holocaust assisting Einsatzgruppen A.
10. SS-Totenkopfstandarte
circa 2,500 men
Formed 11/39 Buchenwald from SSTK Std. 3. Became SS Brigade 1 (as SS Infantry Regiment 10) under Kommandostab RFSS April 1941, then tranferred to 18th SS Horst Wessel division Jan. 1944 as SS-Panzergrenadier Regt. 40.
So two TV verbande were turned into two regiments that then formed the 1 SS brigade. It's not clear when exactly it came into being as it had a couple of slightly different names in a short time span. Dates range from spring '41 to late summer '41 (the source where I got the above info use april '41 which is probably right). What does seem clear from it's record is that while it was a combat unit capable of regular combat operations (of which it conducted several) it was also or perhaps even mostly used for antipartisan duties and Einsatzkommando duties. Sounds like this was one of the most nasty units the waffen-ss had...
So far no luck on the other brigade but since the 1st was attached to the reserves of army group center I bet the second brigade was attached to army group south (and with similar origins).
Edit: the 1 SS brigade was not attached to army group center but was part of the OKH reserves, the command staff of the RFSS to be more precise. It didn't become 'active' till july. Can't find anything substantial on the 2nd brigade, except that it existed at some point.
For those interested I did find this reference to a source:
"PRECHTL, G.M. "Unsere Ehre Heißt Treue": Kriegstagebuch des Kommandosstabes Reichführer-SS - Tätigkeitsberichte der 1. und 2. SS-Inf.Brigade, der 1. SS-Kav.Brigade und von Sonderkommandos der SS. Wien: Europa Verlag, 1984. As I recall, this is a HUGE book - maybe 850 pages or more."
The SS cavalry brigade mentioned seems to have been used in a similar role as the two brigades. It later became the Florian Geyer division.
Narwan