In the field I use an "iMax MagicBox 2.5" HDD Enclosure w/ 13-in-1 Card Reader" bought in 2006(!) with padded carrying case for US$60. No viewing however. Unfortunately, the manufacturer ran into trademark violations with the name iMAX (what were they thinking? ), so it is no longer made under that brand.
Plug in any card CF, SD, etc., press download button, voila, contents are copied to HDD, in separate folders for each download session. The 2.5" HDD can be any capacity, the download firmware only supports a 30GB FAT partition, but any other partitions can be used via computer USB.
The 80GB drive put in mine includes a 1GB bootable partition with Tinycore linux, so I can connect it to any computer, boot into TinyCore OS, gain access to all partitions and the drive(s) in the computer, use the internet connection, etc..
Canon 5Dc, Spotmatics II, F, ESII, Pentax 6x7
S-M-C Takumars 17-500mm (18 lenses), S-M-C Macro-Takumars 50 & 100mm, S-M-C Bellows Takumar, Macro-Takumar 50/4 1:1, S-M-C Takumars/6x7 55-200mm (7 lenses)