Basically, would you allow a Vorpal Ranged Slashing Weapon (maybe a Chakram (sp?) from FRCS)?
Sure. Have you ever
seen Xena?
So, you do agree that it would be stupid to allow an enchantment on the Melee Weapon table to apply to a Ranged Weapon (in this specific case).
No I agree that it would be stupid to take an enhancement which is limited to 5 feet of range and put it on a crossbow. As to actually
allowing it, I think it would be pretty stupid to
disallow it.
Why can't you find these weapons as random treasure?
1> Why can't you find Opposable weapons as random treasure? Or Shatterspike weapons? Or Caustic Burst weapons? Or any of the enhancements that are in supplements?
2> Convenience. There aren't very many slashing ranged weapons. In the core rules - there aren't any. Therefore there's no point in putting Vorpal on the ranged table and telling you to reroll every time you get it for a non-slashing weapon - you'd just reroll every time. Thus, we could expect way less than 1% of the powerful ranged weapons to be vorpal - and if it's less than 1% it may as well not be on the chart.
All not being on the chart means is that it's really rare. Not that you can't make it - but that not many people have. You can't make a ranged vorpal weapon in the core rules - so it's not listed on the core chart. That does not mean that you couldn't make one if you had a non-core weapon which was ranged and slashing.
Heck, by your logic, we wouldn't be able to have a magical chakram
at all - as it isn't on the ranged magical weapons chart in the same book.
Non-appearance on the random item chart means precisely one thing:
it's not on that chart. Do to the enormous wealth of things which can be made - that's hardly surprising. You know what else isn't on the chart? Elvenkind Cloaks of Resistance +1. You can make them, they cost 4,000 gp - but they aren't on the chart. The chart is much more limited than the item creation rules allow items to become.
The inability to make a magic item that doesn't already exist on the treasure chart is something which only happens in video games.
-Frank