Jam-like pack with Lid & mesh pocket

One option would be to contact Chris Zimmer about a custom pack. I talked to him once and he said about $200 for a pack with a frame (I believe the exact price depends somewhat on materials and size but I can't speak for him). Thats more expensive than a Jam but its pretty competative with a lot of the ready mae UL packs out there and you can get exactly what you want.

Thanks. I'm hoping to find something that's available right away…

In that case I'm not sure you'll find exactly what you want.
If a mesh pocket is important check out Mountain Laurel Designs, Gossamer Gear and Six Moons Designs.
I don't think any of them have a top pocket. You can improvise by strapping a small sack to the top. Us one witha roll top so small items don't slip out. If it has a roll top that snaps together you can pass a strap through that hole they create to make sure it never slips off your pack. Worked for me.

What about a ULA Circuit and MLD pack lid? This is what I have.

Perhaps the new GG Gorilla?

http://gossamergear.com/packs/backpacks/gorilla-2012-ultralight-backpack.html

Not sure if they are available yet, or in the US…

http://www.terra-nova.co.uk/Product_Type/Lightweight_Packs/Voyager_45_Pack.html

Take a look at Six Moon Designs Traveler.

It's a panel loader, in case that makes a difference, but it has:
– pocket in the top (where the lid would be in a top-loader)
– mesh front and side pockets
– enclosed pad pocket – NOT mesh
– weighs ~28 oz with the aluminum stay (optional)

I carried one on my Long Trail thru-hike and it performed well. The most I carried was about 35 lbs and it handled it ok but I wouldn't make a habit of it.

See here:
http://www.sixmoondesigns.com/packs/Traveler.html

-Steve