Have you thought of a 'Cigar Oasis I' for humidification? It may not be big enough for you, but they do have them at CI ...
There is also the 'Cigar Oasis II' Electronic Humidifier:
Totally unattended, reliable operation;
Uses only 100% distilled water no chemicals;
Water reservoir is user refillable;
Built in filtration and mold retardant;
Set to maintains the humidity at 70% or user adjustable humidity from 60-80% humidity;
Includes circulation fans to maintain uniform humidity;
Suitable for large humidors, armoires, display cases, etc.;
Overall dimensions only 6 1/2" wide x 5 1/4" high x 13" long;
Adapter plugs into any standard power outlet;
Standard adapter 120VAC - Optional 240VAC.
Regular $290, I've seen them online for $267.00 ...
_______________________________________________________
Moist-N-Aire Humidifier's are another way to go, and I've heard good thigns about them:
If you have a display case, cabinet or end-table size humidor, the Moist-N-Aire is one of the most economical humidifiers you can purchase.
With an all stainless steel construction , this automatically controlled electric unit will humidify an area up to 48 cubic feet (6' x 4' x 2'). For case larger than this, 2 Moist-N-Aire humidifiers can be used. The Moist-N-Aire is available in both a 110-volt (USA) and 220-volt model (Europe), has a built in float so you can easily notice when water needs to be added, and has a reservoir that holds approximately 2 quarts of water.
A separate hygrometer is required to obtain the humidity reading of your humidor. To reach your desired humidity level, make the initial setting on the Moist-N-Aire low, and slowly increase over a period of a few days. Size: 9"W x 5"D x 9"H.
S-1000 / USA --- $155.00 (110V)
S-2000 / Europe --- $170.00 (220V)
