Is there a way to pass parameters "by name" (and not by order) to a batch .bat file?

Yeah you could do something like that though I don't think you can use "=" as a token delimiter. You could use say a colon ":", somebatchfile.bat "SOURC:originalFile.txt" "TARGET:newFile.txt". Here is an example of how you might split the tokens:

@echo off

set foo=%1
echo input: %foo%

for /f "tokens=1,2 delims=:" %%a in ("%foo%") do set name=%%a & set val=%%b

echo name:  %name%
echo value: %val%

Running this would produce this:

C:\>test.bat SOURC:originalFile.txt
input: SOURC:originalFile.txt
name:  SOURC
value: originalFile.txt

[Edit]

Ok, maybe it was too close to bed time for me last night but looking again this morning, you can do this:

@echo off

set %1
set %2

echo source: %SOURCE%
echo target: %TARGET%

Which would produce this (note that I reversed the source and target on the command line to show they are set and retrieved correctly):

C:\>test.bat "TARGET=newFile.txt" "SOURCE=originalFile.txt"
source: originalFile.txt
target: newFile.txt

Note that %1 and %2 are evaluated before the set so these do get set as environment variables. They must however be quoted on the command line.

Other way I quite liked:

set c=defaultC
set s=defaultS
set u=defaultU

:initial
if "%1"=="" goto done
echo              %1
set aux=%1
if "%aux:~0,1%"=="-" (
   set nome=%aux:~1,250%
) else (
   set "%nome%=%1"
   set nome=
)
shift
goto initial
:done

echo %c%
echo %s%
echo %u%

Run the following command:

arguments.bat -c users -u products

Will generate the following output:

users
defaultS
products

A bit late to the party :) This is my suggestion for managing "posix like" options. For example mybatchscript.bat -foo=foovalue -bar=barvalue -flag

:parseArgs
:: asks for the -foo argument and store the value in the variable FOO
call:getArgWithValue "-foo" "FOO" "%~1" "%~2" && shift && shift && goto :parseArgs

:: asks for the -bar argument and store the value in the variable BAR
call:getArgWithValue "-bar" "BAR" "%~1" "%~2" && shift && shift && goto :parseArgs

:: asks for the -flag argument. If exist set the variable FLAG to "TRUE"
call:getArgFlag "-flag" "FLAG" "%~1" && shift && goto :parseArgs


:: your code here ...
echo FOO: %FOO%
echo BAR: %BAR%
echo FLAG: %FLAG%

goto:eof

..and here the functions that do the job. You should put them in the same batch file

:: =====================================================================
:: This function sets a variable from a cli arg with value
:: 1 cli argument name
:: 2 variable name
:: 3 current Argument Name
:: 4 current Argument Value
:getArgWithValue
if "%~3"=="%~1" (
  if "%~4"=="" (
    REM unset the variable if value is not provided
    set "%~2="
    exit /B 1
  )
  set "%~2=%~4"
  exit /B 0
)
exit /B 1
goto:eof



:: =====================================================================
:: This function sets a variable to value "TRUE" from a cli "flag" argument
:: 1 cli argument name
:: 2 variable name
:: 3 current Argument Name
:getArgFlag
if "%~3"=="%~1" (
  set "%~2=TRUE"
  exit /B 0
)
exit /B 1
goto:eof

Save the file as mybatchscript.bat and run

mybatchscript.bat -bar=barvalue -foo=foovalue -flag

You'll get:

FOO: foovalue
BAR: barvalue
FLAG: TRUE