Cats,
That is a completely different lane splitting than what they have in Cali. That bill will only allow us to legally move through traffic during times of congestion, in other words, go to the front of a long light or an accident. In Cali, they can lane split anytime based on what I read in an issue of Motorcyclist.
Also, don't fret losing your piece on your bike. Get yourself a quality holster and it will stay with you when you come off. Don't ask me how I know, but I know.
If you come off in a major way, weapon retention will be the last of your worries.
Mark,
Since I have a CHL, I don't worry about carrying a pistol anymore on the way to the range. However, before I had one, I talked to a few HPD guys and tried to find out if it was legal to have them it in my backpack. While nobody would commit to answering the question all of them seemed to indicate that since the backpack was inaccessible during operation of the vehicle that it could be construed as being similiar to the trunk of a vehicle. However, once you get off, it is accessible and could be considered on or about your person. I don't think there are any AG rulings on that though.
As for rifles, they are legal to have in a vehicle in Texas. I've ridden with the AR on my back and haven't been stopped for it. I'm sure your state laws vary and maybe you could get a lawyer friend to hit your AG for a ruling?