I ran across this at Plant Delights Nursery website, written by Tony Avent. It isn't new by any means, because I probably read it when I was first interested in hosta. I got my first hosta order from PDN too, but more than likely, when I read this I had not a clue that dormancy requirements for hosta would figure prominently in my future. That was back in 2010 spring when I was first ordering hosta. Now 3 years later, it makes more sense to me.

Anyway, I'd like to discuss with other warm climate hosta lovers what they think about this. Maybe crossing the gene pool with some lower dormancy hosta would be a good idea for us zone 9 and hot 8b climates?

I hope they don't mind if I quote from the piece at the website. To see the list of hosta which follows the info, you'll have to follow the link given below.
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Quoting:
Hostas are a genus of plants that seemingly everyone wants to grow... even those who don't live in a good climate for them to thrive. As a general rule, Hostas prefer climates with cold winters and warm summers. For gardeners in southern climates of Zone 9-10, picking the right Hosta can be a daunting task.

Most Hostas must have a minimum winter dormancy requirement of 30 days at temperatures below 43 degrees F. In warmer southern regions, the Hostas that perform their best are those that have lower than normal winter dormancy requirements. The required winter dormancy for a Hosta is genetic and is based on the part of the world where the species involved in a particular hybrid originated (warm climate versus cold). The Hosta species which have evolved in the warmest climates and therefore have the lowest chill requirements include Hosta clausa, Hosta gracillima, Hosta kikutii, Hosta longipes, Hosta montana (southern forms), Hosta nakaiana, Hosta plantaginea, Hosta rupifraga, Hosta sieboldii, Hosta ventricosa, Hosta venusta, and Hosta yingeri. While all Hostas will emerge the following spring after a low-chill winter, they are usually quite weak and proceed to deteriorate during the subsequent season.

The easiest way to determine the dormancy requirements is to observe which Hostas emerge the earliest in spring. There is generally a 75 day emergence date spread between Hosta cultivars in spring. Below is a list of those that emerge extremely early and would make good candidates for trialing in warm climates where there is little or no winter chilling.

Beside each cultivar name are the low-chill species (where known) from which they are derived.
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If my high dormancy hosta need more cooling, I'm wondering if I need to get me a refrigerated locker or a highway van to keep my high-cold requiring hosta in long enough to grow vigorously. However, I have the utmost faith in the genus hosta to adapt to a globe that is warming at all latitudes, and so they will be able to survive. To my way of thinking, they are already adjusting when they go heat dormant....but I'm not a scientist. .

Here is a link that might be useful: Hostas For Warm Climates--PDN Tony Avent