The 2004 bale catalog lists the Doar Ivri plate blocks in 157 different groups (not including sub groups). The groups are separated by Denomination, Type (Slug, Star leaning Left, Star Leaning Right, or No.), Paper type, Perforation, and Distance from the top of the stamp to the control. Of these 157 groups, I have 48 in my collection (30%). I have seen an additional 32 of the groups (20%) listed on E-bay at one time or another. The remaining 50% I haven't seen on E-bay yet (at least, as long as I have been tracking this).
Recently, I decided to look at the these plate blocks in more detail. I started tracking all the listings of these on E-bay (and even checked Delcampe and Stamp Wants). There are 85 plate blocks that came up in my search. 6 of these had significant errors (4 were double perf, 2 were imperf). If I exclude these, the start price of the listing was on average 60% of the Bale 2004 catalog value. However, only 7 of these blocks sold. 3 of the lots that sold were from the batch of 4 with double perfs. The other 4 sold for only 37% of catalog on average. This doesn't even tell the whole story, since of the 4 that sold, 2 sold for less than 20% of catalog value, and 2 sold for just over 50% of catalog value.
It is also interesting that only 18 of the 85 lots were listed in the traditional auction format, while the rest are listed in the store format with buy it now prices. The 2 plate blocks that sold for under 20% of catalog value were both listed in the traditional auction format. That isn't to say there aren't bargains available in the store format. There is a 50 mill plate block, group 141, listed at $19 buy it now. The catalog value of this block is $160. It has been listed since June at this price, and there have been no takers, even at 12% of catalog value. There are 3 other plate blocks listed at less than 25% of catalog value, so this is not an isolated case.
One of the benefits of looking at plate blocks is that they each have serial numbers that make identifying them easy. This allows me to get a more complete look at what is going on with the price of an individual item. For example, one seller listed the 15 mil plate block from group 94 with serial number 1030 3 separate times before it sold (to me). The first time, it was listed in his store at $27 (54% of the $50 catalog value). It went unsold until 10/20/09, when the listing ended. The seller than listed it in a 7 day traditional auction with a start price of $12 (24% of catalog value). Again, it went unsold. It was then listed in another 7 day traditional auction with a start price of $9 (18%). I was the only bidder. I could have taken a chance that it would have been re-listed lower, but I decided to buy it.
There is also a significant benefit to shopping around. There are 10 copies of the 50 mill plate block in group 141 currently for sale. They range in price from $19 to $130 (12% - 81%). Some of the blocks in the middle are listed as LH, while both the high and low priced ones are listed as MNH.
I also see one seller listing the same plate block on E-bay and Stamp Wants. The prices on each site are very different. The 20 mill group 123 plate block is listed on stampwants for $1300 (with the make offer option enabled), and the same plate block is on E-bay for $1400 (again, with the make offer option enabled). The same seller has a 50 mill group 139 plate block for sale on E-bay for $399, while on Stamp Wants, the exact same block (identical serial number) is listed at $500. The same seller also has an imperf plate block of the 5 mill for sale on both sites. It is listed at $900 on Stamp Wants, and a staggering $1200 on E-bay. It definitely would pay to shop around if you are in the market for these high end plate blocks!