In addition to your list from Random House Websters Unabridged are the following additional words ending in "dous" from the "common" word list provided by www.onelook.com and its dictionary links:

blendous, hybridous, nefandous, infandous [obsolete], tardigradous [obsolete];

and the zoological and botanical specialized words -- amphipodous, anarthropodous, annelidous, brachypodous, frondous, gasteropodous, heteropodous, ligniperdous, macropodous, mesomyodous, neuropodous, peristeropodous, phyllopodous, polymyodous, pteropodous, pygopodous, rhizopodous, steganopodous, stomatopodous, trachelipodous

Also from www.onelook.com and its dictionary links are the "not-so-common" word list of additional words ending in "dous":

anidous, arthropodous, branchiopodous, centifidous, cowardous, curculionidous, deccapodous, diabetes insipidous, diplolepidous, diplopodous, discordous, dolichopodous, haemapodous, haplolepidous, heterolepidous, infecundous, laemodipodous, lemuridous, macrocladous, micropodal micropodous, myriapodous, niggardous, octopodous, odous, olidous, pachycladous, pachypodous, pharcidous, polypodous, repandous, sauropodous, schizopodous, sciapodous, scoubidous, sesquilepidous, solipedous, splendidous, surquedous, timidous, turgidous