Hey Tom,
Congrats! You are really good! Phenomenal investigator!
I also did some intense internet search today and finally came to the same conclusions.
That rear fork bearing (1x) is indeed a 6203. Sealed on both sides. 17mmx40mmx12mm
And the front wheel bearings (2x) are 6201. Sealed on one side only. 12mmx32mmx10mm
Brand:
Well, in case I would want to go with a really good high quality brand bearing. So probably from German or Japan. FAG, INA, SKF, SNR, NSK, NTN, KOYO etc. No chinese noname stuff.
So far I found a quite interesting new bearing series from FAG (C-series) with new and better seals against dust and water.
FAG 6201 C 2HRS or FAG 6201 C 2ELS
FAG 6203 C 2HRS or FAG 6203 C 2ELS
(both are permanently sealed on both sides and lifetime greased)
FAG Generation C
http://www.fag.de/content.fag.de/en/products_services/rotativ_products/deep_groove_ball_bearings/generation_c/generation_c.jsp?Searching for bearings is a real science and a challenge. When you check different bearing manufacturer, you will also find different labels, names,terms for the same bearing. But there is a conversion table available to "translate/transform" from one brand to another. Interesting stuff.
I will continue my research for a while, until I made my decision and then I am going to order some for my next tire change.
So Tom, thanks again. You have done a great job again! And your NTN6203LLU/5K is basically the right one. You might consider a different brand though...
Quality Bearings Online
http://www.qualitybearingsonline.com/