I think this pretty much shows that you should use SmashTV and Mikes Midishop because they are not SO expensive. And afterall they support the MIDIBox community 
Correct. The average builder won’t be able to DIY the boards and buy all needed parts for the prices that are offered in our stores. That is the reason I do what I do. If it were about making money, there would not be enough profit to justify doing this all these years. 
Couple minuses i discovered:
SmashTV:
Lower your DIN/DOUT module prices?
Price is tied directly to the average of fluctuating component costs on my end, And my tendency to stick with known quality brands on the parts makes this higher than it could be if I were to use no-name parts of questionable quality. A kit builder should -never- have to wonder if a malfunction is due to a bad (but new) part. In that context even one bad part per 5000 is too many. 
My price is .88€ higher on the DOUT and .23€ on the DIN, so given the rate of decline of the dollar vs other currencies, the difference will probably be automatically corrected sometime next week by the world market. ;D
Get some new LCD’s?
I am trying to scare up some decent deals on these. Cost to stock is very high on these considering all of the sizes/backlight/color variants available. I have to be careful not to over extend myself financially, so properly stocking a few thousand dollars worth of a high cost+low markup item is something I am planning carefully. 
The great surplus deals (like the last one on 2x20s) are few unless you like no backlight. RoHS has made this worse, there are a few good large lot surplus deals here in the US I would be buying for the store if they were RoHS compliant. :-\
And maybe you could sell component kits?
Do you mean a parts kit without the board? I already do by special request. I want to keep the order page simple so it’s not an option there.
I have to comment on your price table for future readers, I realize you know this already but $1 does not equal 1€, and my store prices are in Dollar not Euro.
My added text is in RED below and using this morning’s forex rates:
So here comes the packages:
Package:
Core(without PIC)
SID
DinX4(2-pieces)
DoutX4(3-pieces)
Blank PCB
Reichelt: 55€
SmashTV: 93€ This should read 69.97€. ($93.00 USD=69.97€)
Mikes: 69€
DIY-Saves: 14€
Package:
Core(with PIC)
SID
DinX4(2-pieces)
DoutX4(3-pieces)
Blank PCB
Reichelt: 62€
SmashTV: 112€ This should read 76.71€. ($101.95 USD=76.71€)
Mikes: 90€ I get 80.10€?
DIY-Saves: 28€
Package:
4x Core(without PIC)
4x SID
DinX4(2-pieces)
DoutX4(3-pieces)
Blank PCB
Reichelt: 84€
SmashTV: 138€ This should read 137.66€. ($183.00 USD=137.66€)
Mikes: 107€ I get 144.70€?
DIY-Saves: 23€
Best Regards
SmashTV