From what I've seen, con eq is in low abundance compared to the other stats in the game. Con is probably the most stat in the game, and I wonder why there are a lack of good con eq (hell there is even a lack of crap con eq). This really hurts those players who are trying stick with their characters but have low con because of deaths.
More con eq please
There is a common armor socket you can use on to put +1 CON.
One of the mithril pieces gives +2 CON.
Rings of life give con. I have seen other rings that give con + hit dam.
It is one of the penalties of dieing, the lack of con.
This is heavy on the non commoners classes.
Some people have healing sets to regen faster by boasting con.
If there is something is a lack of dex restoring equipment that is useful.
There is also a nice little set of earrings that is +2 con, and very easy to get 
There aren't a million different things that give you con, but what's there is a good number of easy to get non-rare things that give you a couple extra conpoints each. Which is all someone who's down a couple points from deaths needs.
In my experience con eq is the easiest to get, then dex and str are about the same with a slight advantage to dex eq.
Some people have healing sets to regen faster by boasting con.
If you have 18 con max but you have boosted it with 5 more - (18)^5 - does it help you regain like you have 23 or you still regain with the usual 18?
I've always noticed it healing around the same rate and never actually helping, though that's from times when I was actually paying attention to things.
If you have 18 con max but you have boosted it with 5 more - (18)^5 - does it help you regain like you have 23 or you still regain with the usual 18?
The usual 18. Boosting a stat beyond your racial max doesn't do any good except provide insurance against stat-draining attacks.
Dex gives an ac bonus.
Dex gives an ac bonus.
Not dex beyond your max.
Pali is correct.
Having a stat above your racial max doesnt give any advantage other than a buffer zone against spells or skills that weaken that stat.
simple example..
having STR 18(18)+5
means if you get weakened you would have
STR 17(18)
instead of
STR 12(18)
May seem overkill, but if your lets say...a halfling blademaster going up against a shaman...well an intelligent shaman will weaken, plague and poison you in hopes to take advantage of your lower STR stat. Having the +X to the stat just makes them have to remove more STR before your weapon drops.
As for the OP's request, there is quite a bit of +con eq in the game. The socket for + con alone can be used in several pieces at once as well.
Yup... I can think of a single ring you can BUY from a CITY NEAR YOU. That will give you +6 con alone.
At lvl 1 there is an easy +3 con on offer.
At lvl 5 - 15 (depending on class/race etc) you get easily +2 more from one pice of eq.
That's +5 con, I fail to see how you'll need more - but htere is a +1 floater and that socket that can be used in multiple places.
L-A
Perhaps I should ask for more con GOOD eq. Granted they are some solid very common pretty bad con eq out there, but still +str, and +dex are more in abundance.
Seriously, there is ALOT of con gear out there. All you need to do is get your A into G and go find it.
The same thing that Evils can wear for +con a good can wear as well at such low lvls. I practically keep the same thing I wear from lvl 1 to at least 30 and the only thing that really changes is weapons because I don't want to wield a practice weapon the entire time. By then you can have your stats maxed through trains or at least your con, I tend to always keep my con 2 below the max so I can max it in two wearable items at lvl 1 before lvling up, and by the time I hit lvl 5-10 I can switch those two things out with another item that still gives me +con and +hit/dam if needed. They don't need a boost to it I wouldn't ever think, they're far too abundant everywhere practically, you just have to find them and never go below 2 of your max on con when adding them because it makes it that much easier to max it with +con eq.