I would think that you should get quite a lot of responses to this as there are several camps when it comes to this subject. The first lesson I learned as a young hotrodder is that there is no replacement for displacement; ergo a 440 has more power than a 340 (in stock form). That said and many years later I can say with a degree of certainty that as it relates to streetable power, you can get a SB to produce BB power, however it is a sliding graph, meaning if you worked on both a SB and BB simultaneously and did essentially the same mods to each, the power levels would remain apart.
To be very honest, all of this is really moot unless you are building a race car and trying to accomplish something specific (HP level, speed, ET, whatever). As stated, you can make a SB produce 500+ HP especially given today's technology and parts. Sure you can make a BB produce far more but you arrive a diminished point of return, meaning that at a certain point more HP isnt necessary or even desirable unless you are specifically after that for whatever reason.
You have to look at the car holistically and identify what you want or intend to do with it and then build to that. I would not hesitate to use a SB to achieve any streetable HP goal, likewise I wouldn't shy away from a BB either. For me its about the "package" and what I want the end result to be, if you want to be able to say your car is a BB car then go that way, if on the other hand you dont care and are only concerned about overall performance (speed, handling, stopping, etc.) then you should definitely be considering a SB. Not saying a BB car cannot handle or stop, but the weight advantage of a SB coupled with cost might make more sense.
As to how the engines deliver their respective power; you are correct in that typically a BB will exhibit stump pulling torque whereas a SB comes on mid to high RPM (generally, I am sure many will chime in about this). That said, this effect can be negated/improved by gear selection and suspension set up. I have personally owned and seen SB cars that just kick ass; super fast off the line and pull like freight trains. Here again you are blessed living in a time when almost anything is possible; with advent of overdrives, 6 or 8 speed automatics you can literally have your cake and eat it too.
As to RPM limits, well here again if you are talking about relatively stock engines using stock fasteners; I would say your current understandings very far off. In the old days we knew that taking a BB (especially a 440) past about 6800 was not a good idea and you were probably going to grenade it. Sure there were/are some who push them into the 7K+ territory but IMO its an accident looking for a place to happen. The Chevy guys have the same issues with 454's. The 383 (and 396) seem to slightly more forgiving in that you will probably float the valves before it lets go but you never know. Consequently, 340's would run up to the low 7K range and some more; hell I took a 318 to 8K and held once trying to blow it and it wouldn't, did make any power at that level as the valves were floating but it held together.
You really need to develop an overall scheme for the build and talk to some engine guys like Mike at Muscle Motors, or the guys at Indy, Keith Black, etc. Talk to all of them and see what feedback you get. they are all going ask the same questions; "what do you want to do with it", "what are you going to out it in", etc.
The internet is great but it can drive you crazy. Talk to people who build engines for a living and actually Dyno them; they can tell you no BS exactly what works and what doesn't. Every car guy out there can tell you about this car and that car, this engine and that engine, but without verifiable quantifiable data its just another war story.
