Google-sheets – How to use arrayformula to copy/paste rows en masse

I'm stress testing an application that relies on importing spreadsheets. I can populate those spreadsheets with dummy data, but sometimes I need thousands upon thousands of rows (the only thing that needs to change from one row to another is the email, where it can auto increment like so: user1, user2 etc).

I don't want to copy/paste 10,000 rows, I'd rather I have an arrayformula or something where I simply state: given the contents of row1, repeat X times and concatenate the user field by a number (I know how to do the last part, it's the publication of the rows number that I find difficult).

Sample sheet

Script workaround

I wrote this quick Python script to do what I'm trying to do here using a spreadsheet formula:

#!/usr/bin/env python
import csv

with open("orders.csv", 'w') as myfile:
    header =["Site","Email","Password","Size","NotificationEmail","NotificationText","PostiveKW","NegativeKW","StyleNumber","EarlyLinkMonitorKeywords","NewPageMonitorKeywords","FirstNameBilling","LastNameBilling","address1Billing","address2Billing","cityBilling","stateBilling","zipCodeBilling","countryBilling","phoneBilling","houseNbBilling","FirstNameShipping","LastNameShipping","address1Shipping","address2Shipping","cityShipping","stateShipping","zipCodeShipping","countryShipping","phoneShipping","houseNbShipping","friendlyName","NameOnCard","DOB","cardType","CardNumber","CardExpirationMonth","CardExpirationYear","CardSecurityCode","billingEmail","paypalEmail","paypalPassword","CheckoutDelaySeconds","CheckoutOncePerWebsite","OrderThreads"]

    wr = csv.writer(myfile, quoting=csv.QUOTE_ALL)
    wr.writerow(header)

    numberOfRows = 10
    while numberOfRows > 0:
        row=["StressTest","guest.805642","guest","3","","","xxx","","","http://www.footaction.com/product/model:95404/sku:23419012/jordan-6-rings-boys-grade-school/black/white/","","Mark","Escude","105 Putney bridge lane","","Simpsonville","SC","29681","US","9018345575","","Mark","Escude","105 Putney bridge lane","","Simpsonville","SC","29681","US","9018345575","","6676","Mark Escude","0/0/0","AMEX","3.71E+14","1","2020","562","Escudem@mac.com","","","0","FALSE","100"]
        numberOfRows = numberOfRows-1

        wr.writerow(row)