The Collaborative International Dictionary of English v.0.48:

Commodious \Com*mo"di*ous\, a. [LL. commodiosus, fr. L. commodum
   convenience, fr. commodus. See Commode.]
   Adapted to its use or purpose, or to wants and necessities;
   serviceable; spacious and convenient; roomy and comfortable;
   as, a commodious house. "A commodious drab." --Shak.
   "Commodious gold." --Pope.
   [1913 Webster]

         The haven was not commodious to winter in. --Acts
                                                  xxvii. 12.

   Syn: Convenient; suitable; fit; proper; advantageous;
        serviceable; useful; spacious; comfortable.
        [1913 Webster]

WordNet (r) 3.0 (2006):

commodious
    adj 1: large and roomy (`convenient' is archaic in this sense);
           "a commodious harbor"; "a commodious building suitable
           for conventions" [syn: commodious, convenient] [ant:
           incommodious]

Moby Thesaurus II by Grady Ward, 1.0:

61 Moby Thesaurus words for "commodious":
   advantageous, ample, amplitudinous, appropriate, banausic,
   beneficial, broad, capacious, comfortable, comfy, contented,
   convenient, cozy, cushioned, cushiony, cushy, deep, easeful, easy,
   employable, expansive, expedient, extended, extending, extensive,
   far-reaching, fitting, friendly, functional, good for, helpful,
   homelike, homely, homey, infinite, lived-in, luxurious,
   of general utility, of help, of service, of use, peaceful,
   practical, pragmatical, proper, relaxing, reposeful, restful,
   roomy, serviceable, snug, soft, spacious, spreading, useful,
   utilitarian, vast, voluminous, warm, wide, widespread