I'm planning on trying cabinets from Custom Service Hardware for my basement office. A 12" wall of base and uppers plus a 24" pantry cabinet in maple with plywood sides comes to $1750.

They are shipped R.T.A. Solid maple doors & face frames, 5/8" plywood sides and backs, dovetailed drawers, with soft close undermount slides. Certainly good enough for an office I would think.

Here is a link that might be useful: Custom Service Hardware

Just called them, unfortunately, they don't have home office stuff. Due to a window and other needs, I do need the shorter office cabinet setup. DARN IT!

why not try a furniture store or even office store. no need for a custom counter top, but you can always add on later.

Ikea kitchen cabs are built with 30 inch boxes and adjustable height legs. Maybe you could use a shorter leg...

CabParts.com will sell to industry professionals, and they'll make the boxes to custom size.

or try BudgetKitchenCabinets.com?
they have desk cabinets(but no bookcases)
http://www.budgetkitchencabinets.com/price/base_desk.html

They're part of CabinetryDirect.com, which will do custom sizing (and maybe wil make a bookcase to order)
http://www.cabinetrydirect.com/pricing/custom.shtml

I suppose you could use their base cabinets, and get an unfinished-furniture place or a local carpenter to tackle the bookcases.

There's Scherrs.com, perhaps....

I believe Lowe's also offers white cabinets "off the rack". You should check those out to see if the price is more in your range. They aren't that hard to install yourself.