hmmm... okay, here's an idea...
Set up your FedEx and UPS to quote to a max weight limit as you did in MonsterCommerce, if over the limit, either not offer or >grey< them out... But, you also offer RFQ, that way a customer can always request a freight quote, (even if under your 70 pound limit). You might even be able to set it up to use "free freight" for orders over $x,xxx...
The above sounds like a "simple" php edit.... per what Ajah referred to above. I haven't looked at the code yet.
Other situations like mine with Glass and Hazardous are still sounding like we need an additional field in the product database that I can test against since weight isn't a factor... Even if something as simple as "freight only" is added to the database. This is something in my opinion that we really need.
I have seen MANY posts over the last 2 years or so asking for some sort of way to specify freight/truck shipping.... and most of those have gone unanswered. Shipping modules are so important that I would think the zencart team would put more attention to it.
I have three large projects coming up and two are "must have freight" ... because of this I have been forced to look at perhaps using a paid cart like ProductCart which appears to have a full featured shipping and payment modules...
<sigh> No easy solutions!
Let me know how the UPS Freight and FedEX freight goes! When is this going to be offered?
-cj
p.s. the RFQ module came from OScommerce!