When you finish a feature, the feature keeps selected in the modeltree. What I usually do is copy paste with Ctrl+C and Ctrl+V. It´s pretty fast and intuitive for me.
I only have a mapkey for paste special since there´s no straight shortcut.
You can make a mapkey for that if you want:
mapkey \ ~ Command `ProCmdEditCopy` ;~ Command `ProCmdEditPaste`;
Another option is to use the find tool to select the last feature and copy paste it:
mapkey q @MAPKEY_NAMERepeat with find;@MAPKEY_LABELRepeat;\
mapkey(continued) ~ Command `ProCmdMdlTreeSearch` ;~ Open `selspecdlg0` `SelOptionRadio`;\
mapkey(continued) ~ Close `selspecdlg0` `SelOptionRadio`;\
mapkey(continued) ~ Select `selspecdlg0` `SelOptionRadio` 1 `Feature`;\
mapkey(continued) ~ Open `selspecdlg0` `LookByOptionMenu`;\
mapkey(continued) ~ Close `selspecdlg0` `LookByOptionMenu`;\
mapkey(continued) ~ Select `selspecdlg0` `LookByOptionMenu` 1 `Feature`;\
mapkey(continued) ~ Activate `selspecdlg0` `EvaluateBtn`;\
mapkey(continued) ~ Select `selspecdlg0` `ResultList` -1;\
mapkey(continued) ~ Activate `selspecdlg0` `ApplyBtn`;~ Activate `selspecdlg0` `CancelButton`;\
mapkey(continued) ~ Command `ProCmdEditCopy` ;~ Command `ProCmdEditPaste`;
And no, I think you can´t use the space bar for mapkeys
Jose