Print the tree Parts with 0.1mm Layerheight:

2 x Mount
1 x LedBar

What Parts do You need? Get this from Your electronics Seller:
8 LED's Ultrabright White
2 (or more) Resistors 12 Ohm (I use 13.5V for this Installation!)
depends on the Powersource You use (I use the heated Bed PS)
some Wires to connect the Lightbar with the PS (see Pictures)
and for sure, a Solderiron...

Solder the LED's, Resistors and Wires like shown on the Picture.

Mount the Lightbar on the UltiMaker and have Fun!
You can use two in Parallel on each Side, so print all the Items 6 times.

Tell me what You think and what You may wish in future Versions.

Update:
On the Ledbar LED's, every 2nd LED have an Offset of 10° because some LED may have only a 15° Beam...