Sample project that creates a customizable picker from scrollable views, functionality needs tweaking slightly. Titanium Project, works for iOS.

customPicker.js

//"THE BEER-WARE LICENSE": As long as you retain this notice you can do whatever you want with this stuff.
//If we meet some day, and you think this stuff is worth it, you can buy me a beer in return Jamie Buckley

var screenWidth = Ti.Platform.displayCaps.platformWidth;
var screenHeight = Ti.Platform.displayCaps.platformHeight;

var win = Ti.UI.createWindow({
  fullscreen: true,
	width: screenWidth,
	height: screenHeight,
	backgroundColor: 'white'
});

var pickerSelectedValue = '0';

//Select Row Size
var rowSize = 30;
//Input the picker Data here
var picker1Data = ['Tea', 'Crumpets', 'Bacon', 'Chocolate', 'Cider', 'Cheese', '1', '2', '3', '4', '5'];
var pickerX = 0;
var pickerY = 0;

var pickerSelectedValue = '0';

//Create the scrollView that will be the basis for our picker
var picker1 = Ti.UI.createScrollView({
	height: rowSize * 6,
	width: (screenWidth * 0.3),
	backgroundColor: 'black',
	layout: 'vertical',
	verticalBounce: false,
	top: pickerY,
	left: pickerX
});
picker1.scrollTo(0, rowSize * 6);

//When the picker has finished being scrolled, snap to the nearest picker row
picker1.addEventListener('scroll', function(e){
	picker1.addEventListener('dragend', function(){
	if(e.y <= rowSize * 2 || e.y >= rowSize * 12){
		if(e.y <= rowSize * 2){
			picker1.scrollTo(0, rowSize * 2);
			pickerSelectedValue = (rowSize * 2 / rowSize) + 2;
		}
		if(e.y >= rowSize * 12){
			picker1.scrollTo(0, rowSize * 12);
			pickerSelectedValue = (rowSize * 12 / rowSize) + 2;
		}
	}
	else{
		picker1.scrollTo(0, Math.floor(e.y / rowSize)*rowSize);
		pickerSelectedValue = ((Math.floor(e.y / rowSize)*rowSize) / rowSize) + 2;
	}
	Ti.API.info(Math.floor(e.y / rowSize)*rowSize);
	});
});
win.add(picker1);

//For creating picker labels
function newPickerItem(labelText){
	var PI = Ti.UI.createLabel({text: labelText, color: 'red', center: 0});
	return PI;
};

//For creating picker views
function newPickerView(){
	var PV = Ti.UI.createView({height: rowSize, width: Ti.UI.FILL, backgroundColor: 'transparent'});
	return PV
}

blankArr = ['', '', '', ''];
pickerData2 = ['', '', '', ''];

var pickerData = blankArr.concat(picker1Data, pickerData2);
Ti.API.info(pickerData);

//Systematically add each item from the array as rows to the picker
for(var i = 0; i < pickerData.length; i++){
	newItem = newPickerItem(pickerData[i]);
	newView = newPickerView();
	newView.add(newItem);
	picker1.add(newView);
};

//View that highlights the currently selected row
var selectedRow = Ti.UI.createView({
	top: rowSize * 2,
	height: rowSize,
	width: (screenWidth * 0.3),
	backgroundColor: 'transparent',
	borderColor: 'red',
	borderRadius: 2,
	borderWidth: 1,
	touchEnabled: false,
	left: 0
});
win.add(selectedRow);


//When pressed will return the currently selected value as an alert
var acceptButton = Ti.UI.createButton({
	title: 'Accept',
	height: screenHeight * 0.1,
	width: screenWidth,
	bottom: 0
});
acceptButton.addEventListener('click', function(){
	alert(picker1Data[pickerSelectedValue]);
});
win.add(acceptButton);

win.open();