With a level 16 requirement on tinkering it could mean that it takes at
least that level to travel wherever or complete whatever quest. Anyway,
some things you might want to look out for when looking:

1) The butcher knife quest. The knife is now lore/no drop so its very
likely that someone somewhere wants it. Anyone that has the identify spell
and that they can get one themselves and cast on it? I don't have the
spell much less a spellbook lol and since its no trade I'm at a dead end...
On a related note go to the magic hall in Ak'anon and ask Tergon 'Who is
Meldrath?'

2) Non-rusted Blackbox. Very rarely when killing clockworks in Steamfont
you get a 'Blackbox' (Non-rusted) and the warrior guild leader won't take
it. Again, maybe with the identify spell it might say who it belongs to.

3) Gnome in Erudin. Go to the jail cells by the bank and there's a gnome
in there doing time for something about smuggling Erud's tonic into Qeynos.

4) The Great Span. This quest probably has nothing to do with tinkering
but sounds interesting and it looks like nobody has ever completed it. In
one of the houses in S. Qeynos there's an NPC named Hansl Bigroon or
something like that. On the floor in his house (across from the tax
collector) is a note that is supposed to be delivered to Antonius Bayle's
messanger. Basically he's working with 3 other engineers (listed on the
note, one of them is Jogl) to create a giant bridge to Odus. Nobody has
found out who gets the note, but each of the engineers drops a decapitated
head as loot when killed. You take quite a bit of faction hits for
collecting them, I'd imagine there must be a fairly good reward for this
quest...

-Luke