No - not many games allow you to specify the save location.
You could "fool" The Witcher [and other games] by creating a symbolic link between the Witcher save folder and your Dropbox folder though.
To do it you need a free utility from Microsoft called Junction [you can get it here:
http://technet.microsoft.com/en-us/sysinternals/bb896768.aspx]
To set up the link you would do the following:
1) Download the junction utility and extract it somewhere you will remember [or, to make it available in your system path, put it in Windows\System32 folder]
2) Create a folder for your Witcher saves in your Dropbox folder [eg: My Documents\Dropbox\Witcher Saves]
3) Move the save files from your Witcher save folder [default My Documents\The Witcher\saves]
4) Delete the original Witcher save folder [see step 2 for location]
(NOTE: Deleting the folder is necessary because the junction will create a symbolic link using the same name, it is treated as a folder and therefore cannot be created if there is already a folder of the same name)
5) Open the command prompt [start, type 'cmd' in the search box, hit enter]
5 a) If you extracted junction to a non path location [eg: C:\util] then navigate to that folder: [ex: cd C:\util]
6) use the following command line to create your junction point [change folder locations to suit your system]:
junction "C:\Users\MyUserName\Documents\The Witcher\saves" "C:\Users\MyUserName\Documents\Dropbox\Witcher Saves" To remove a junction use
junction -d C:\Path\to\junction
