Hi Edward Tung,
Some of the older folks at the tables at gun shows can take a bit to warm up to and vice versa.
I sense a lot of the folks behind the tables are tired from traveling and setting up and then have their hands full watching their tables and those of their buddies to make sure wares do not "walk away". I think they also get tired and probably a bit short tempered with "tire kickers".
Some older, conservative sellers, seeing your $ 20K bankroll may have assumed the worst...i.e you are trying to flash money around to buy a piece without the paperwork, you might just be showing-off a bit and are not a serious buyer, you might be a BATF agent, your money is drug-money, etc...(not saying or implying any of the above are true in your case...

).
If you tend to be like many younger folks nowdays that dress in the hip-hop, "gangsta" style; I suspect a generational gap may have been at work...as well.
Sometimes racial/ethnic barriers come into play...I find this from time to time in my gun show travels in the mid-west; especially after 9/11 and with my ethnic heritage...I can appear to come from several trouble spots in our world today.
I do find folks at gun shows watching tables for their table-mates who may be walking the gun show floor themselves. In Tulsa, I had to go back to one vendor's tables 6-7 times over a 2-day period before I finally got to meet him, introduce myself, shake his hand, and then negotiate the sale of a nice luger. Patience on my part paid off, as I became the owner of a very nice pistol.
There are a couple of C&R gun shops near your home : San Jose Gun Exchange in SJ and Mike Krause' Krausewerks, in San Mateo. I have found folks at both shops willing to talk lugers, if you catch them at the shop during off-peak times.
I am sure no one would take your $ 20K bank roll lightly in either shop. For 3/4 of that bank roll, Krause can easily sell you a nice, custom-made Luger in .45 cal. He has one on display in the shop and takes orders.
p.s. I saw a couple of your previous posts on the original Luger Forum a few years back. If you use terms such as "old prunes" and "old croaks" too freely, this might not work with some folks in person...
Regards,
Pete... <img border="0" alt="[typing]" title="" src="graemlins/yltype.gif" />