[Senior Patek Moderator]
Undeniably, many collectors have shown a strong preference for larger sizes during the last 10 to 15 years, and this is also the direction Patek is taking for most of its newer models, including the Calatrava collection.
I like numbers, so your reply made me look up some interesting data in response. First off, we currently have VERY few in-catalog "men's" models (defined for simplicity's sake as 5xxx- or 6xxx-references, though this is not entirely accurate) of size less than 39mm, and NONE less than 38mm. The only Calatrava included in the former group is Rare Handcraft Ref. 5088/100P, for which it is not even possible to submit new applications.
To be honest, while I'd be fine with "experimenting" in other areas of Patek's production, I want the Calatrava line to play it VERY safe for now. Since March of last year --- when the first group of 2022 releases included a number of new references, but intentionally left out all the sports models! --- the popularity of the entire Calatrava collection has literally NEVER been so high in generations. It would be insane, in my view, to take any chances so early in the process....be it for a less-than-popular design, or size, or anything else
[NOTE: I don't work for Patek, but I always provide amazing advice😂]
As for the rest of Patek's current collection, interestingly, the very few men's models of size smaller than 39mm include as many as three iterations of Ref. 5396. This is a gorgeous AC reference, with the unusual feature of being in Patek's collection for over 17 years, by means of a large number of R and G gold versions. (The R-011, which I bought in 2010 and saw many siblings come and go in between, is still in production today!). This is DEFINITELY a watch I would advise you to acquire, assuming you are interested in this type of traditional complication --- good looking, extremely classy, and historically/horologically VERY relevant.
Then, out of more than 140 other models, I'm afraid I only have THREE pieces of good news for you!
The first two come from the Grand Complications catalog, namely Ref. 5160/500G (a 38mm perpetual calendar with a hand-engraved case back, which is pure art on the wrist), and the highly surprising Ref. 5373P that we announced last year, at 38.3mm. You need to be prepared to wire north of $200k to Patek for either model, but at least for the 5160, that's the only downside I can see
Some GREAT news I have is however called 5230P (or 5231G, in its enamel version)! This is our most recent WT, an amazing complication that has written the history of this Brand, and is available --- for less than $100k in both cases --- at 38.5mm.
Perhaps even more interesting from your perspective, this is THE best example I can give you of Patek *downsizing* its modern offering, since the immediate predecessor of the 5230, Ref. 5130, was 39.5mm in size (in turn, this marked an increase with respect to the earlier WT, Ref. 5110). Size aside, I'd warmly encourage you or any other good collector to request a 5230, Andrea (or if accessible, of course go immediately for a 5231)!
I hope this helps, or at least that it put things more in perspective for everyone. It was also interesting for me to look into this topic! ;-)