I used to have the vk-60 monos in my system and paired them with the Genesis 300 speakers. This was an excelllent combo. You will not get "deep bass" out of the vk-60's. But when combined with the dedicated bass amp of the Genesis speakers, you wll retain the clean, warm and liquid mid-range the vk-60's provide and, generally speaking, will achieve much better bass performance than you would otherwise by triying to drive almost any other speaker full range with the vk-60's.
Another suggestion is the Dunlay SC-IVa's. The IV-a's go pretty low and have a sensity of 91db. I've heard this combo a few times and it is really nice. With Dunlay out of business you should get a great price on the IVa's. But unfortunately "size matters" and the IVa's are big.
As an aside, I traded my vk-60's for vk-150se's and I run Dunlavy SC-VI's. The low bass is excellent but I wouldn't say that my system produces "deep bass".
If deep bass is a primary objective, if I were you I would either pick a speaker that is amenable to bi-amping or one that integrates well with a sub-woofwer. You won't get deep bass out of the vk-60's.