This is the specs for the Rom-Arrange ruggedised PC's for an interesting comparison. This cost me about $2.5K with monitor. The Baytrail option (for Android OS style system) is a fair bit cheaper, but I wanted windows OS.
Don't ignore the interface options you need. I like the range of inputs for example Rom-Arrange provides, especially the 4 x Com ports. I have no spare Com ports left on mine, all 4 Com ports are permanently connected. More would have been nice in hindsight.
Might help as an example of some of the systems out there from a price v hardware point of view.
Rom-Arrange PC Fanless L5 Core I5.
Intel i5-4300U Haswell ULT
SO-DIMM (DDR3-1333 / 1600Mhz) 8 GB (16 Max)
-or-
INTEL® Baytrail
SO-DIMM (DDR3-1333/1600Mhz) 4 Go (16 Max)
HDD:
1 x 2.5 "SATA Device (available)
1 x mSATA SSD 120GB Device (up to 1 to optional)
Front:
2 x USB 2.0
4 x COM
2 x Audio
1 x oN / OFF button
1 x reset button
Rear:
2 x HDMI
4 x USB 3.0
2 x USB 2.0
2 x RJ45
1 x Audio
2 x Antenna hole
1 x DC in
Stuff:
DC 9-24V
AC_90 ~ 240V / DC_12V_5A / 60W
0 ° C ~ 50 ° C
2.2kg
185 x 60 x 142 mm
Aluminum